<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <link rel="stylesheet" type="text/css" href="tree.css">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
  <script src="tree.js"></script>
</head>

<body>

  Дерево с подгрузкой узлов (рабочее):
  <ul class="Container" id="tree">
    <li class="Node IsRoot IsLast ExpandClosed">
      <div class="Expand"></div>
      <div class="Content">Каталог</div>
      <ul class="Container">
      </ul>
    </li>
  </ul>

  <script>
    tree("tree", "data.php");
  </script>


</body>

</html>